Many of the genes that affect how well a child can read at secondary school have an impact on their maths skills too, researchers say.

Scientists found that around half of the genes that influenced the literacy of 12-year-olds also played a role in their mathematical abilities. The findings suggest that hundreds and possibly thousands of subtle DNA changes in genes combine to help shape a child's performance in both reading and mathematics.

But while genetic factors are important, environmental influences, such as home life and schooling, contributed roughly the same amount as genetics in the children studied, the researchers said.

"Children differ genetically in how easy or difficult they find learning, and we need to recognise, and respect, these individual differences," said Robert Plomin, professor of behavioural genetics at Kings College London and an author on the study.

"Finding such strong genetic influence does not mean that there is nothing we can do if a child finds learning difficult. Heritability does not imply that anything is set in stone. It just means it may take more effort from parents, schools and teachers to bring the child up to speed."

In the study, 12-year old twins and unrelated children from around 2,800 British families were assessed for reading comprehension and fluency, and tested on mathematics questions from the UK national curriculum. This information was then analysed alongside the children's DNA.

Oliver Davis, a geneticist at University College London, said: "We looked at this question in two ways, by comparing the similarity of thousands of twins, and by measuring millions of tiny differences in their DNA. Both analyses show that similar collections of subtle DNA differences are important for reading and maths."

The study did not identify specific genes linked to numeracy or literacy, and researchers do not know what the various gene variants do. But they may affect brain development and function, or other biological processes that are important for learning both skills.

The findings build on previous studies showing that genetic variations among British schoolchildren explain most of the differences in how well they perform in exams.

Writing in the journal Nature Communications, the authors explain that understanding how genes affect children's abilities "increases our chances of developing effective learning environments that will help individuals attain the highest level of literacy and numeracy, increasingly important skills in the modern world".

Chris Spencer at Oxford University said: "We're moving into a world where analysing millions of DNA changes, in thousands of individuals, is a routine tool in helping scientists to understand aspects of human biology. This study used the technique to help investigate the overlap in the genetic component of reading and maths ability in children. Interestingly, the same method can be applied to pretty much any human trait, for example to identify new links between diseases, or the way in which people respond to treatments."